Multistory constructions, such as apartments or multiplex houses, are constructed to allow sewage from each story to be discharged through the vertical pipe of the building.
Most of the pipes used in the construction buildings are formed from a synthetic resin such as P.V.C. or the like and thus cause a problem that the flame or smoke is spread to the upper stories through the pipe in the case of a fire.
For that reason, the pipe material used for the through holes of the floor or wall is required to have flame resistance. Thus, there have been used cast-iron pipes or double-layered pipes that include an outer layer composed of fiber-reinforced mortar having flame resistance on the outer side of the pipe made of a synthetic resin material.
However, the double-layered pipes made of fiber-reinforced mortar involve a complicated production process with low productivity and high production cost, and the cast-iron pipes are difficult to construct due to heavy load.
As a solution to this problem, a fireproof expandable resin composition including an inorganic or organic expanding agent added to an ACE resin is formed into a sheet or a paste. The sheet of the fireproof expandable resin is wound around the synthetic resin pipe penetrating into the floor or wall, or the fireproof expandable resin in the form of paste is applied onto the synthetic resin pipe. The expandable resin composition expands when heated in the case of fire, to close or almost close the synthetic resin pipe softened by the temperature of the fire. This can prevent the flame or smoke from spreading upwards.
Although winding or applying the expandable resin sheet or paste may contribute to the lightweight of the pipe material, it is troublesome to perform the process of winding the expandable resin sheet or applying the expandable resin paste during the work, which makes the construction process too complicated and possibly leads to occurrence of defects during the winding or applying process, thereby causing the flame or smoke to spread upwards.